Printing-plate.



G. R. GORNWALL.

PRINTING PLATE.

APPLICATION FILED 111111.20, 1905. BBNBWBD DBO. 31, 1912.

lQ. Patented Aug. 12, 1913.

'aeeaese yat GEORGE B. CORNWALL, OF RYE, NEW YORK, A'SSIGNOB TO AMERICAN PLANOS-WH COMPANY, A CORPORATION OF WEST VIQBGINIA.

PRINTING-PLATE.

Specification of Letters Patent.

.application mea March ao, 1905, serial No. 251,097. Renewed December s1, 1912. serial No. 739,564.

4lo alli/whom t may concern:

Be it known that'I, GEORGE R. CORNWALL, a citizen of the United States, residin at Rye, in the county of Westchester and tate of New York, have invented new and usef ful Improvements in Printing-Plates, ofv

which the following is a specification.

The invention relates to printing plates. An object of the invention is to produce a printing plate' whichil shall be exceedingly durable bothras against -wear and against injury; which is capable of yielding workV of a high quality and at very great speed: which is easily and inexpensively made; and from which the desigm'while having the qualities above pointed out, may be readily removed when so desired and another design readily substituted therefor and having the same general properties. v'Ihese and other objects will more fully appear from the following description.

The invention consists in the novel steps,

nor the relative proportions of the parts thereof, this form of illustration beingbest suited to elucidate an invention of this character.`

Of the drawings: Figurefl shows a plate carrying a design; Fig. 2 is a section on the line II-II of Fig. 1; Fig. 3 is a similar section showing a modified. structure of the plate; and Fig.l .4 is a section showing a form of plate particularly adapted for use with a rotary form member.

In the illustration of a printing plate embodying a form of the invention, l represents the non-printing portion of the surface of such a plate, saidportion being of a planographic character, i. e. being adapted to reject ink either from the nature of the surface or from its adaptability to hold an ink-rejecting substance. The design portion of the surface of the plate is represented by the reference numeral 2 and is of a material adapted to take ink readily or to holdan or film carrie ink-taking substance: The general disposition of the elements or portions constituting the' surface is in layers, as is diagrammatically shownin Figs. 2, 3 and 4. In Fig. 2 the design-bearing element is shown as a layer fil'm superposed upon the layer or film 2. In Flg. 3 the layer 2 serves also as the body of the plate. It will be understood that these lms or layers may be exceedingly thin, as the plate will be thoroughly efficient wherever there is suflicient film or layer of the metal or other material so that there are no breaks or discontinuances therein at any point on the surface which should be covered by said metal in order to produce the desired printing effect.

Various materials may be used for constructing the plate but certain metals lend themselves peculiarly to the various functions of planographic printing. Among such metals zinc or aluminum constitute desirable elements for the ink-rejecting layer or film while copper, iron and steel constitute desirable elements for the ink-taking elements. It is not essential that the two ele ments of the surface be different materials, as the same material may be used for both, when it is adapted to assume the roperties, under proper treatment, for constituting the ink-taking and ink-rejectin'gelements of the surface.

In the form shown in Fig. 2 the layer or film may be an electro-deposition of copper upon a bed or plate 3, which may be of iron or steel, or other suitable material, while the topmost layer may be of zinc or aluminum. In Fig. 3 the metal which is to constitute the design is represented as also constituting the body of the plate and it may be of iron or steel, or other suitable metal, and carrying the layer l thereon. In Fig. 4 is shown a section of a plate which is of a form adaptable for use with a rotary form member.

The layer 2 may be deposited by dipping the body 3 in molten metal, or it may be deposited electrolytically, or otherwise. The said surface 2 may further be prepared as to its physical state or condition so as to fit -it to the highest degree to perform its functions as the design-carrying elements of the by a base 3 and the other element of the surface'ls shown as a layer or planographic printing surface, and the layer or film l at the'proper time may, vif desired,

also receive a coating Aor layer of inkrejecting material. The design may be placed upon the film or layer 2 in a roper medium which may be especially a apted with reference to the manner in which the layer or film 1 is to be superposed upon the layer or film 2. This may also be done by dipping or it may be done electrolytically. Where the said layer or film 1 is to be deposited electrolytically, a.y proper resist is placed on that part of the .surface corresponding to the design, so that While the remainder of the surface of the fil-In orlayer 2 will receive a deposition of the metal 1 the design will be free therefrom. After the film or layer 1 has been deposited the material of the design which was placed upon the film or layer 2 may be removed, and the plate will then consist of the layer 1 adapted for the ink-rejecting surface of the planographic plate while the design will be defined in the inferiorilm or layer of metal 2.

The part 2 of the printing surface may be carried as a film or layerupon a supporting body or it may be a part of the supporting body itself, the only requisite bein that it shall be of a material capable of ta ng ink or color readily or of belng so treated as to be madev to take ink or color readil In Fig. 2 the said part 2 is shown as a layer upon asupporting body while in Figs.

3 and 4 the said part 2 of the printing S111' face is shown as being a part of the'supporting body.

Al plate embodying the features of this invention may also be produced by taking a base or support which shall constitute the layer or part 2 or upon which the layer or part 2 may be deposited.A The layer or part 1 may then be deposited upon the base or support, or layer 2, and this may be done byY dipping the said base or support in molten metal, or by electro-deposition, or otherwise. The surface of the plate in all portions excepting the design may be then covered with a resistant material in `any suitable or convenient manner. An etching or other reducing agent may then be applied to the surface for the purpose ofetchin or cutting away the exposed portions of t e metal. A reducing agent which possesses great activity with respect to the layer or part 1 may be used and which, at the same time, is comparatively inert with'respect to the layer or partv 2. By using such an agent it is practicable to entirely etch or cut away the portions of the-layer or part 1 which are not protected by the design and, at the same time, to leave the layer or part 2 unattacked.

In Fig. 4 of the drawings is illustrated a form of plate which is of great practical utility; The plate is made in the form of a segment of the cylinder andis adapted to form a removable portion of the surface of the form cylinder of a rotary press. A material well adapted for such a cylinder is iron or steel on account of comparatively low cost, its strong ink-taking properties, as well as for other reasons. Such a plate may be dipped in a metal adapted to constitute the ink-rejecting portion of the planographic printing plate, such as zinc, While said metal is in the molten state. The design may befthen brought down to the surface or part 2 by any suitable means, and it may be bitten out by a suitable reducing agent as hereinabove described.

When it is desired to use the plate for another design, the film or layer 1 may be removed by using a proper reducing agent having greater affinity for the constituent metal o`f said layer or film 1 than for the constituent metal of the layer or film 2, and in a similar manner the film 2 may also be removed if so desired. In certain forms of the invention the removal of the lm or layer 1 obliterates the design entirely and leaves the plate in condition to receive a new From the foregoing it will be seen that a planographic printing plate has been provided having its surface in layers; that the layers may be of metal; that the design is v carried by an inferior layer; that the de. sign is carried in a durable material and not in a soft and perishable medium. The design being carried in an inferior layer of material also protects 'it from injury and also from the effects' of attrition during the printing operation as well as from the action of the cleaning -solutions that may be used on the plate. While such a plate has ormation, etc., common to flexible sheets or plates.

The invention, in its broader aspects, is

not limited to the 'particular embodiment shown, nor to any particular embodiment,

`nor to the particular materials shown nor to any particular materials, as changes may be made without departing from the main principles of the invention and without sacrificing its chief advantages.

What I do clam as my invention, and de: sire to secure by Letters Patent, is:

1'. A planographic printing plate consisting of an iron plate, or layer, carrying upon its surface a layer of zinc or aluminum so disposed as to leave the surface of such iron plate, or layer, exposed to form the design.

2. A planographic printing plate consisting of an iro'n plate, or layer, carrying on its surface a layer of aluminum or zinc, said layer of aluminum or Zinc being so disposed that the iron plate, or layer, forms the inktaking portion of the printing surface.

3. A planographic printing plate having a layer, or element, of iron, and in the form of a segment of a cylinder, and having a coating or layer of Zinc, or aluminum, said layers together constituting a planographic printing surface.

4. The process l of producing a planographic printing plate which comprises placing upon a design-constituting surface a layer of ink-rejecting material and then removing portions of said layer in the form of the desired design so as to leave the designconstituting element exposed in said portions, said two elements thus forming the surface of the printing plate.

The process of producing a planographic printing plate which comprises covering a suitable base With a layerof design-constituting material, then covering said layer with a terial, then removing said ink-rejecting malayer-of ink-rejecting mal terial from the design-constituting layer,` in the shape or form of the design, the remaining portion of the ink-rejecting layer and the exposed portion of the design-constituting layer then constituting the printing surface.

6. The process of producing a planographic printing plate which comprises depositing upon a design-constituting surface a layer of ink-rejecting material, protecting said layer of ink-rejecting materia in the non-design parts and then removing said layer in the design parts, the exposed portion of the design-constituting surface and the unremoved portions of the ink-rejecting layer then constituting the printing surface.

In testimony whereof I have signed my name to this specification in the presence of tWo subscribing Witnesses.

. GEORGE R. CORNWALL.

Witnesses:

WINTHROP POND,

JOHN D. MORGAN. 

